The invention relates to a compact modular unit to be mounted in a milking stall having at least one pipeline system, which provides an operative function in connection with a milking process of an animal in the milking stall. The compact modular unit (4) includes a casing (28), which defines an inner space of the compact modular unit (4), an electric control unit (23), which is mounted in the inner space of the compact modular unit (4), and an indicator (27, 50), which is arranged to display information related to the milking processes in the milking stall. Furthermore, the compact modular unit (4) includes a component (9, 10, 17, 52) of the pipeline system which is mounted in the inner space of the compact modular unit (4).